docs: def connected(self, client):
          """Call this method when a client connected."""
          self.clients.add(client)
          self._log_connected(client)
          self._start_watching(client)
          self.send_msg(client, WELCOME, (self.pickle_protocol, __version__),
                        pickle_protocol=0)
          profiler = self.profiler
          while True:
              try:
                  profiler = profiler.profiler
              except AttributeError:
                  break
          self.send_msg(client, PROFILER, type(profiler))
          if self._latest_result_data is not None:
              try:
                  self._send(client, self._latest_result_data)
              except socket.error as exc:
                  if exc.errno in (EBADF, EPIPE):
                      self.disconnected(client)
                      return
                  raise
          if len(self.clients) == 1:
              self._start_profiling()